Expanding tool



J. B. HOOD EXPANDING TOOL June 1, 1943.

Filed Oct. 9, 1941 a 7 Q IT EN my g INVENTOR (/A MES 5. H000 M622; 3-

A TTORNEX Patented June 1, 1943 EXPANDING TOOL James Hood, New York, .N. Y., assignor to Aircraft Screw Products Company, Inc., Long Island City, N. Y., a corporation of New York Application October 9, 1941, Serial No. 414,327

4 Claims.

The present invention relates to a tool for securing wire coil inserts in the threading of a tapped hole. Wire coil inserts here in consideration are used in order to provide a; boss of more or less soft material, as for example aluminum, with a hard and resistant internal threading which permits a stud to be repeatedly screwed in and out without injury to thethread convolutions in the boss. Screw connections of such kind are disclosed, e. g.-in the U. S. Patent No.

2,150,876; however, I wish it to be understood that my invention is not limited to the use in connection with wire coilsof the particular cross-section shown in the said patent.

In accomplishing a screw'connection of the said type certain difficulties are frequently encountered since it happens that the external threading of a stud when being screwed into the insert engages only ashort length ,of the latter, and that further turning of the stud causes a relative movement between insert and boss rather than between insert and stud. In other words, if e. g. in a cylinder of an internal combustion engine a wire coil insert is used in the tapped hole for a spark plug it occurs that the spark plug when being applied thereto catches only one view respectively of an insert of the mentioned type with ends adapted to be anchored in the boss after its insertion;

Fig. 3 is a side elevation, partly in section of an embodiment of the invention;

Figs. 4 and 5 are sections along lines H and 5-5 respectively of Fig. 3;

Fig. 6 is a sideelevation, partly in section, at I another embodiment of my invention, and

Fig. 7 is a similar elevation. of a modification thereof.

Referring now first to Figs, 1 and-2 of the drawing, I0 is an insert of the'mentioned-typc whose wire is so coiled that the pitch of the cone or two convolutions of the insert and then turns the insert so as to screw the latter forward in the tapped holeand to urge the advancing endof the insert into the cylinder space. It is obvious that such happening may be the cause of severe damage.

It is the purpose of the present invention to overcome these difliculties by forcing the convolutions of the coil after its insertion into the thread grooves of the boss, and in certain cases I also shape the ends 01 the wire coilso that they can be anchored in the boss by expansion of the coil or at least of the end portions of the coil after its insertion. The present invention aims, therefore, to provide a tool with the aid of which volutions I I substantially corresponds to that of the threading of the tapped hole for which the insert is destined, and the diameter is preferably 'so selected that the wire springs into the thread. I grooves of the boss to which it is to be app d- The cross-section of the wire may either be diamond-shaped .or it mayhaveany other-suitable or conventional. cross-section; The ends-l2 and I3 of the insert may have inward bends ll, l5 and may be provided with outwardly directed sharp points or edges II, II which, however}.

should not substantially projectbeyond the outer periphery of the coil prior to its insertion as clearly shown in Fig. 2.-' Npw, it will-be apparent that if such coil of a hard metal is inserted inn. tapped hole provided with a corresponding threading in a soft metal boss or nut, and if,

then, the coil and/or particularly its ends are expanded from the interior, the co'nvolutions oi the insert will be more firmly embeddedin the-thread grooves oi the boss; and the pointed ends I, II

" will bite into the softer material-oi the boss the desired internal pressure in substantially radial direction can be easily exercised. The tool according to the invention comprises a body with a slotted threaded end which can be screwed into an insert of the mentioned type, and then expanded by internal wedging action of a member e or members actuated from the other end of the tool.

Further details and objects I will be apparent from the description given hereinafter and the accompanying drawing showing two embodiments thereof by way of example.

In the drawing: i Figs. 1 and 2. are a side elevation and a front of the invention owing to the bends M, II bemi forced outward,

whereby the insert will be secure y anc This may be accomplished with 'the'tcol according to the invention and illustrated Figs 3 to 5. The tool comprises a substantially tubular body It whose one end lfiuis'so shappd'that a torque about its axis can be applied thereto. For 7 this purpose, the end is of'the embodiment of Fig. 3 is hexagonal so'that, a conventional' wrench may be used in connection therewith; "The other end 20 is provided with an external threading ll of a pitch and diameter substantially corresponding to the pitch and interior diameter 01' th insert for which the tool is destined; Similarly, the shape of the threading 2| is preferably selected according to the cross-section of the insert wire. 7

Hence, if e. g. the latter is round, the threading 2| should have a segment-shaped groove. and it the wire is diamond-shaped, the threading 2| should have a V-shaped groove as shown in Fig. 3. Thus, the end of the tool can be easily screwed into a coil such as shown in Figs. 1 and 2 after the coil having been inserted in a boss. Body I8 is provided with a plurality of longitudinal slots 22 extending from the end 20 towards the other end I9 of the body. The length of the slots 22 should be so selected that the desired engagement of the end 20 can be obtained within the elastic limits of the material of the body I8.

A flange or shoulder 23 is provided on body I8 in order to limit the depth to which the end 20 can be screwed into the wire insert. In certain. instances it is advisable to apply a washer 24 to the flange 23. This washer is shown in Fig. 3 as a flanged ring with a spring ring 25 embedded therein and overlapping the flange 23 in order to prevent loss of the washer by inadvertence. The inner bore 26 of body I8 is cylindrical over its major portion. Near the body end 20,- however, the bore has two oppositely directed conical faces 21 and 28.

Interiorly of the bore 26 and guided therein is a tubular plunger 29 movable lengthwise and having an end 20 with a taper corresponding to the cone of the face 21 and in engagement therewith. At the other end of the plunger 29 a cap 3| is provided with a central bore 32 of a diameter equal to that of the plunger. drawing cap 3| and p1unger29 are shown as separate pieces, it will be understood that they shaped head I52 open towards the handle of the tool and interiorly threaded at I53. A cap screw I54 engages the threading I53. In the embodiment of Fig. 6 the cap screw consists of a hollow stud portion I55 with an external threading and a flanged shell portion 456 secured to the stud Although in the v may consist of one piece only. A bolt 33 is arvranged interiorly of'plunger 29 and its one end tion. The contours 42 of the prongs adjacent to the cap 3I are cam shaped so that the distance of the axis-of pin 38 from the cap 3I is shorter I when the handle is axially extended as in Fig. 3

than such distance when the handle is tilted or turned through 90 about the pivot. Now it will be clear that by adjusting nut 36 it can be obtained that simultaneously plug 35 will be in enagement with face 28, cone 30 with face 21, and cam 42 with the surface of cap 3I while handle 39 is in the'axial position of. Fig. 3. If, then, handle 39 is tilted the cam action will urge the two cones 30 and 35 towards each other thereby expanding the end 20 of body I9 owing to their wedging effect on faces 21 and 28 respectively. Furthermore, by turning the nut 36 in the one or the other direction the maximum diameter to which. the end 20 will be expanded by tilting handle 39 can be adjusted within certain limits.

Depending on the lfind of member to which an insert is to be secured and/or its accessability from below or above, it will be preferable to use a tool which can be adjusted near its threaded end as shown in the embodiment of Fig. 3, or near its handle-providedend, as it is the case in the second embodiment of my invention illustrated by Fig. 6. This tool has a body I I8 withhead I I9, threaded end I20, flange or shoulder I23, slots I22, cylindrical bore I26 and cone'faces I21 and I28, all substantially like the equivalent parts whose reference numbers are lowered by one hundred in the tool shown in Fig. 3. The washer 24 of the last-mentioned tool has been omitted in, FIg. 6 because it has been found that its presportion, e. g. by a pin I51. The shell I56 may be knurled as shown at I58, and may be provided with a gradation or scale I59 readable opposite a mark I60 on the head I52 ofmember I29 in order to facilitate the correct adjustment of the tool. A bolt I33 similar to bolt 33 of Fig. 3 is passed through the bore of the stud portion I55 of cap member I54 and through plunger I29. The bolt is provided with an eye I31 at its one end and carries a cone-shaped plug I35 at its other end. The plug I35 bears against a washer I6I which is retained by a pin I62 secured to the bolt I33. A handle 39 with cam face 42 is pivoted on a pin 38 passing the eye I31 in the same manner as described with reference to Fig. 3. a

Fig. 7 shows a modification of the tool of Fig. 6. In this modification, body 2I8 which in other respects is equivalent to body I I8 has a cylindrical extension 220 of the hexagonal portion 2I9. The tubular plunger 229 axially movable in body 2 I8 is provided with a longitudinal groove 250 for engagement with pin 25I, and projects with an externally threaded end 252 from the extension 220. A cap screw 254 engages the threading at 252. It is knurled at 258 and encompasses with its beveled and scale-provided rim 259 the extension 220 which carries the mark 260. Since the plunger is prevented from rotation in body 2I8, the eiIective length of the plunger will be indicated by the relative position of mark 260 opposite the scale on rim 259 provided the plunger is shifted to the right-hand side in Fig. '1 without expanding the body 2I8. Rod I33 axially movable in plunger 229 is passed throughthe bottom of the cap screw 254 and is provided with a cam handle 39 in the same manner as described in connection with Fig. 6. In other respects, the tools of Figs. 6 and '1 are alike, and it will be clear that they serve the same purpose and are operative in a like manner.

The tool according to the invention may be used in the following manner:

After the insert of the type shown in Figs. 1 and 2 is inserted in a boss or nut, the tool with the handle in axial position is screwed into the insert, the nut 36 of the tool of Fig. 3 or the cap screw I54 in Fig. 6 being so adjusted that little resistance is encountered in this operation. The depth to which the threaded end may enter the insert is limited by the body shoulder 23 or I23 with or without a washer 24. Then, the handle 39 is tilted whereby the two cones are pulled towards each other to effect a wedging action against the conical faces 21, 28 or I21, I28 with the result that the slotted tool body {will be expanded. Owing to such expansion, the bends I4 and I5 of the insert will be pressed outward and. the

pointed ends I6, I1 will be forced into the material of the boss or nut. When the tool is expanded beyond the rate where the bends have the same inner diameter as the coil convolutions,

the latter will alsobe expanded and tightly.

pressed into the thread'grooves of the boss or nut. If a first expansion is insuflicient to embed the insert convolutions and/or points I and I5 deep enough in the boss, the handle may be restored to its original axial position and the nut 36 or cap I54 may be so adjusted that the threaded tool end fits the insert'which had been widened owing to the first operation of the tool. If, then, the handle is again tilted additional internal pressure will be exercised on the insert whereby the latter will be deeper embedded in .th boss or nut thread. After the completion of the expanding, operation the handle will be returned to its original position whereupon the tool can be easily screwed out of the insert;

In the foregoing, the tool according to the invention has been described in' itsapplication to inserts whose'ends must be anchored inthe boss or nut in order to prevent shifting of the insert when a tight fitting stud or like memberis being screwed in. However, even with inserts of the type described in the above-mentioned Patent No.

2,150,876 where no anchors are required owing to the fact that the insert-shape and wire crosssection insures immovability of the insert relatively to the boss in view of the friction between insert and bossbeing greater than between insert and stud, the expansion of the insert subsequent to its insertion is highly advantageous. If the insert is firmly seated and forced by'the tool against the thread surfaces in a radial direction there will occur simultaneously a compression of the thread convolutions of the boss which renders the material of such convolutions, particularly if it is a soft metal, stronger and more resistant to the stresses to which the threading is subjected in use. Also, better heat transfer char- 3 bodiments thereof illustrated and described hereinabove but by the scope of the appended claims.

I claim: 1. A tool for securing awire coil insert in the internal threading of a tapped hole, comprising a substantially tubular'body having one end longitudlnally slotted and provided with an external screw threading substantially corresponding to the internal shape of the insert for which the tool is destined, theslotted portion of said body being provided with two internal oppositely tapering cone faces, a tubular member interiorly of said body and having one end tapered and in engagement with one of said cone faces and its other end projecting from said body. a rod member including a cone-shaped, pips-like end in engagement'with the other conejgface oisaid body. one of said members being composed of two parts provided with interengaging screw threads whereby the active length of said member is adiustably variable, and cam means pivoted to the other end of said rod and in engagement with said tubular member so as to urge said plug and said tapered end of the tubular member against the respective cone faces of said body.

2. A tool for securing a wire coil insert in the internal threading of a tapped" hole, comprising a substantially tubular body having one end longitudinally slotted and provided with an external screw threading substantially corresponding to the internal shape 01' the insert for which the tool is destined, theslotted portion of said body being provided'withtwo internal oppositely tapering cone faces. a hollow plunger axially movable in 'said body, said plunger having one of its ends tapered and in engagement with one of said cone faces of said body, the other end of said plunger including means to adjustably vary the length of c said plunger, a rod longitudinally movable within acteristics are secured which is of great importance if the. insert is used in an assembly as, e. g. that of a spark plug and cylinder head. Furthermore, the expanding tool owing to its adiustment feature is useful to control the pitch diameter or size of the tapped hole with assembled insert Similarly, the tool'permits the use of undersized taps by expanding the hole with v a cap screw in engagement with said internal assembled insert to the finished thread 'pitch without departing from my invention which is not limited by the particular disclosure of the emsaid plunger, a conical plug secured to the one end of said rod and engaging the other cone face of said body, and a cam mechanism in operative re- .lation to said plunger and said rod for shifting them in axial direction relatively to each other.

3. A tool as claimed in claim 2, wherein said plunger comprises a cup-shapedhead projecting from said tool body and threaded internally, and

threading, said cap screw, having a'central' bore for the passage of said rod, and markings on said plunger head and said cap screw to indicate their relative adjustment.

4. A tool as claimed in claim 2, wherein said other end of the plunger projects from said tubular bodyfland said means comprise .an external .1 threading of saidother plunger end and a cap screw engaging said threading and being provided with a hole of its bottom through which said rod' is passed, and withmarkings opposite said tubu- 19: body to indicate the effective length of said plunger.

JAMES B. HOOD. 

